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May 29, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
NaN3--->Na+N2 How many moles of Na are produced if 3.5 moles NaN3 react?
Friday, November 20, 2015 by Mathew

General Chemistry
Calculate the standard heat of formation of acetaldehyde , 2C(s) + 2 H2(g) +1/2 O2 (g) ---> CH3CHO(g) given the following information? CH3CHO(g) + 5/2 O2 (g) --> 2H2O(l) + 2 CO2(g) DeltaH rxn =-1194 KJ H2(g)+ 1/2 O2 (g) --> H2O (l) DeltaH rxn =-286 KJ/mol C(s) + O2(g...
Friday, November 20, 2015 by ChemLove

CHEMISTRY
2BrF3(g)Br2(g) + 3F2(g) STANDARD ENTHALPY?
Friday, November 20, 2015 by KD

chemistry
According to the reaction below, how many grams of lithium oxide could be produced from 3.1 moles LiCl? 4 LiCl + O2 → 2 Li2O + 2 Cl2
Friday, November 20, 2015 by chemo

chemistry
According to the reaction below, how many grams of lithium oxide could be produced from 3.1 moles LiCl?
Friday, November 20, 2015 by chemo

Chemistry-Dr.Bob
A solution is prepared by mixing 50.0mL of 0.001 M HCl and 10.0 mL of 0.200 M NaCl. What is the molarity of chloride ions in this solution? My work: (0.001 mol/L)((0.05 L)= 0.005 mol HCl (0.200 mol/L)(0.01 L)= 0.002 mol NaCl 0.005+0.002=0.007 mol of chloride ions 0.007mol/(0....
Friday, November 20, 2015 by Sanaya

Chemistry
A sample of Br2(g) takes 38.0 min to effuse through a membrane. How long would it take the same number of moles of Ar(g) to effuse through the same membrane?
Thursday, November 19, 2015 by Alex

Chemistry
CO(g) effuses at a rate that is ______ times that of Xe(g) under the same conditions.
Thursday, November 19, 2015 by Alex

chemistry
a gold nugget and a silver nugget have a combined mass of 14.9g. The two nuggets are heated to 62C and dropped into 15.0mL of H2O at 23.5C. When thermal equilibrium is reached, the temperature of the H2O is 25.0C. Calculate the mass of each nugget. Denisty of H2O=0998g/mL ...
Thursday, November 19, 2015 by Jule

Chemistry
Zinc - .5 grams HCl- .2 moles Find the Mass of ZnCl2 [How would you solve this?]
Thursday, November 19, 2015 by Derrick

Chemistry
I have the mass of one element and the moles of a compound, How do I find the mass of it'd Product? [Zn + 2HCl = ZnCl2 + H2] (Slove for mass of ZnCl2)
Thursday, November 19, 2015 by Derrick

chemistry
what is the molarity of the KCI solution.
Thursday, November 19, 2015 by Anonymous

chemistry
Write the molecular,complete ionic, and net ionic equations for the reactions that occur, if any, when solutions of the following substances are mixed: a) nitric acid and potassium carbonate b) sodium bromide and lead nitrate c) acetic acid and calcium hydroxide d) calcium ...
Thursday, November 19, 2015 by Lyndsay

Chemistry
1.) Watch the animation, and observe the titration process using a standard 0.100 M sodium hydroxide solution to titrate 50.0 mL of a 0.100 M hydrochloric acid solution. Identify which of the following statements regarding acid-base titrations are correct Drag items A-F to: ...
Thursday, November 19, 2015 by LuigiR

Chemistry
A solution of 0.316 M KOH is used to neutralize 16.0 mL H3PO4 solution H3PO4(aq) + 3KOH(aq) ¨ K3PO4(aq) + 3H2O(l) If 30.3 mL KOH solution is required to reach the endpoint, what is the molarity of the H3PO4 solution? Molarity = ____________
Thursday, November 19, 2015 by LuigiR

Chemistry
What properties do metalloids display, and where are metalloids found on the periodic table?
Thursday, November 19, 2015 by Sara

Chemistry
Why did Mendeleev leave gaps in his early periodic table, and what was the ultimate importance of the gaps?
Thursday, November 19, 2015 by Sara

Chemistry
A student titrates a 25.00 mL sample of HCl. If 20.50 mL of 0.175 M of KOH is required to reach the end point, what is the concentration of the HCl? 25.0 mL HCl x 1L/1000 mL x 0.175 M/1 L = 0.004375 mol HCl 0.004375 mol HCl/20.50 mL KOH x 1000 mL/1 L = 0.213 M HCl (I'm ...
Thursday, November 19, 2015 by Linda

Chemistry
P4 (g) + 3O2 (g) <-> P4O6(s) At a particular temperature, Keq = 4.6. If [P4O6] at this temperature is 1.2M, calculate the concentration of P4 and O2 I'd rather have someone tell me how to do it, so I can do it myself since it's in preparation for an exam.
Thursday, November 19, 2015 by Gemma

Chemistry
What is the molality of each of the following solutions? 1)Dissolve 0.610 mol of citric acid, C6H8O7, in 1.35 kg of water. 2) Dissolve 0.200 mg of KBr in 5.50 mL of water. 3) Dissolve 4.05 g of aspirin, C9H8O4, in 145 g of dichloromethane, CH2Cl2. For some reason I keep ...
Thursday, November 19, 2015 by Rach

Chemistry
I'm solving for the mass of PEG for my 500ml solution, however I don't know what density should I use to convert 50g PEG/kg H2O? Should it be of the H2O or of PEG? Thank you very much! This is my solution: Concentration: 50g PEG/kg H2O Vol= 500 ml or 0.5L ?g PEG= 50g ...
Wednesday, November 18, 2015 by KIM: Please Help!

chemistry
how many liters of ammonia at STP are required to produce 4.65 grams of hydrogen fluoride?
Wednesday, November 18, 2015 by Anonymous

Chemistry
What is the pH of a solution resulting from the addition of 10.0 mL of 0.17 M HCl to 50.0 mL of 0.16 M NH3? Assume the volumes are additive. Kb of NH3 = 1.8 ✕ 10-5.
Wednesday, November 18, 2015 by John

chemistry
If 5.29 g of CuNO3 is dissolved in water to make a 0.370 M solution, what is the volume of the solution?
Wednesday, November 18, 2015 by Rasschael

chemistry
You have a 250ml solution of 0.13M calcium iodate. How many grams of potassium iodate need to be added to the solution to begin to precipitate calcium iodate? The solubility product constant for calcium iodate is6.47 *10^-6. B) you have a 250ml solution of 0.13 M calcium ...
Wednesday, November 18, 2015 by anonymous

Chemistry
What minimum volume of 14.0 M hydrochloric acid would be required to completely dissolve a 600.0 −g iron bar? I'm getting around 2.3 L but it's saying it's incorrect...
Wednesday, November 18, 2015 by Jorge

chemistry
You have a 250ml solution of 0.13M calcium iodate. How many grams of potassium iodate need to be added to the solution to begin to precipitate calcium iodate? The solubility product constant for calcium iodate is6.47 *10^-6. B) you have a 250ml solution of 0.13 M calcium ...
Wednesday, November 18, 2015 by anonymous

Chemistry
What is the function of a salt bridge in a galvanic cell? 1. To permit electrons to flow through the solution. 2. To maintain a steady flow of reactants from the cathode to the anode. 3. To form complex ions with the products of oxidation at the anode. 4. To maintain ...
Wednesday, November 18, 2015 by Anonymous

Chemistry
A solution is prepared by dissolving 3.0 × 10-4 mol of AgNO3 and 3.0 × 10-5 mol of K2CrO4 in 1.00 liter of solution. With respect to Ag2CrO4 (Ksp = 1.9 × 10-12), is the resulting solution saturated, supersaturated, or unsaturated? I know you do [Ag][CrO4} but...
Wednesday, November 18, 2015 by Anonymous

Chemistry
a 6.0 mole sample of Ca3(PO4)2 and a 12.0 mole sample of SiO2 react in an evacuated vessel. after one of the reactants is fully consumed, how much of the gas is created? How exactly would you solve this problem? Would you have to find the molar mass of both sides and divide by...
Wednesday, November 18, 2015 by Allison

Chemistry
A chemist prepared a solution by dissolving 52.0 g of hydrated sodium carbonate in water to a total volume of 5.00 dm3. The concentration was determined to be 0.0366 M. Determine the formula of the hydrated sodium carbonate.
Wednesday, November 18, 2015 by Billy

Chemistry
Calculate the value of theshielding constant if the first ionosaton energy of Helium is 3.98x10ᴧ -19 J/mol
Wednesday, November 18, 2015 by Roderick

Chemistry
One half-cell in a voltaic cell is constructed from a silver wire electrode in a .25 M solution of AgNO3 . The other half-cell consists of a zinc electrode in a .001 M solution of Zn(NO3)2. Calculate the cell potential I have no idea and am so stressed, Help please
Wednesday, November 18, 2015 by Anonymous

Chemistry
What is the net ionic equation of potassium carbonate combines with strontium hydroxide?
Wednesday, November 18, 2015 by Anonymous

Chemistry
What is the net ionic equation of potassium carbonate combines with strontium hydroxide?
Wednesday, November 18, 2015 by Anonymous

Intro to Chemistry
Does the Periodic table have any kind of pattern for brittleness? If so, what is it? For example, the elements on the left are more brittle, while the ones on the right are less brittle.
Wednesday, November 18, 2015 by Claire

chemistry
Maximum mass of water in combustion of 20g hydrogen?
Wednesday, November 18, 2015 by Anonymous

chemistry
At room temperature (25 °C), the gas ClNO is impure because it decomposes slightly according to the equation 2ClNO(g) Cl2(g) + 2NO(g) The extent of decomposition is about 4%. Based upon this, the approximate value of ΔG°298 for the reaction at that temperature is ...
Wednesday, November 18, 2015 by annoymous

Chemistry
Silver chloride has Ksp=1.6x10^-10 and silver cheomate has Ksp=9.0x10^-12. We have 1.00 liter of a solution contains both nacl(0.10M) and Na2cro4(0.10M) solid AgNo3 is added slowly and the solution is stirred well. a) which precipitate first Agcl or AgCro4? B)what are the ...
Wednesday, November 18, 2015 by Anonymous

chemistry
please show the step by step for theoretical yield /yield % of 1.963g NaHCO3-Na2CO3
Wednesday, November 18, 2015 by Anonymous

Chemistry
Calculate the pressure of 4.80g of ozone, O3, in a 2.45 L flask at 25 degrees C. Assume that the ozone completely decomposes to the molecular oxygen. 2O3(g) --> 3O2(g) Calculate the pressure inside the flask once the reaction is complete.
Wednesday, November 18, 2015 by Sarah

Chemistry (Check)
What is the volume of the gas in a balloon at -195 degrees C if the balloon has been filled to a volume of 5.0L at 25 degrees C? Vf = 1.3L
Wednesday, November 18, 2015 by Sarah

Chemistry
Calculate the density of methane gas, CH4, in kilograms per cubic meter at 25 degrees C and 956 mmHg. I got .8252 g/L but am getting confused with the converting units.
Wednesday, November 18, 2015 by Sarah

Chemistry - radioactivity
Hello Dr.Bob, could you please help me with this problem: Which of the following nuclides are most likely to decay via beta decay? a)200 78 Pt b)192 78 Pt c)188 78 Pt d)196 78 Pt
Tuesday, November 17, 2015 by Laurus

chemistry!
a) Find the pH at the equivalence point when 40ml of 0.025 M of methylamine (NH2CH3 and Kb = 4.4x10^-4) is titrated with 0.025 M HCl. b) The Kf for the complex ion Ag(NH3)2+ is 1.7x10^7. The Ksp for AgI is 1.5x10^-16. What is the molar solubility of AgI in a solution that is 2...
Tuesday, November 17, 2015 by Freddy

Chemistry (Help)
Calculate the DHrxn of C57H110O6 (s) + O2(g) --> CO2(g) + H2O(l) with DHf. C57H110O6(s) -390.70 O2(g) 0 CO2(g) -393.5 H2O(l) -285.840 I balanced the equation: 2C57H110O6 (s) + 163O2(g) --> 114CO2(g) + 110H2O(l) and my work: DHrxn = [(114x -393.5)+(110x -285.840)] - [(2x...
Tuesday, November 17, 2015 by Anonymous

Chemistry (Help)
Calculate the DHrxn of C6H12O6 (s) + O2 (g) --> CO2 (g) + H2O (l) with DHf. C6H12O6(s) -1260.04 O2(g) 0 CO2(g) -393.5 H2O(l) -285.840 I balanced the equation: C6H12O6 (s) + 6O2 (g) --> 6CO2 (g) + 6H2O (l) and my work: DHrxn = [(6x -393.5)+(6x -285.840)] - [(1x -1260.04...
Tuesday, November 17, 2015 by Anonymous

Chemistry
A student adds 5.50 g of dry ice (solid ) to an empty balloon. What will be the volume of the balloon at STP after all the dry ice sublimes (converts to gaseous )?
Tuesday, November 17, 2015 by Marquette

Chemistry
If you have a 578 g of fat (tristearin) stored in your body, how much heat will be produced when it is metabolized? tristearin is C57H110O6 The chemical reaction: C57H110O6(s) + O2(g) --> CO2(g) + H2O (l) DHf: C57H110O6(s) -390.70 O2(g) 0 CO2(g) -393.5 H2O(l) -285.840 I don...
Tuesday, November 17, 2015 by Anonymous

general chemistry
Determine the concentrations of Na2CO3, Na , and CO32– in a solution prepared by dissolving 2.57 × 10–4 g Na2CO3 in 1.50 L of water. Express all three concentrations in molarity. Additionally, express the concentrations of the ionic species in parts per million...
Tuesday, November 17, 2015 by Anonymous

Chemistry
What is the unit m^-1? The question I'm working on says "an electron in the hydrogen atom makes a transition from an energy state of principal quantum number nt to n=1. If the photon emitted has a wavelength of 95 nm, what is the value of nt? I was trying to use the ...
Tuesday, November 17, 2015 by Quinn

Chemistry
The standard entropy change for 1.00 moles of Ar as it evaporates at -185.7 °C (∆H°-185.7 = 1558 cal mol-1) is? 1. 17.8 J mol-1K-1 2. 87.5 J mol-1K-1 3. 15.0 J mol-1K-1 4. 46.0 J mol-1K-1 5. 74.5 J mol-1K-1 6. none of the previous answers I thought I would use ...
Tuesday, November 17, 2015 by Anonymous

chemistry
Calculate the ionic strength of a solution that contains 1.45g Na3PO4 in 0.500L of solution.
Tuesday, November 17, 2015 by tithi

Chemistry
Calculate the pressure in an evacuated 250mL container at 0 degrees C when the O2 in 1.00 cm^3 of liquid oxygen evaporates. Liquid oxygen has a density of 1.118 g/cm^3.
Tuesday, November 17, 2015 by Sarah

Chemistry
A solution contains 0.50M Nh3 and 1.50 M Nh4cl. What is the maximum concentration of mg2+ that can be present in such a solution without precipitating Mg(oh)2?
Tuesday, November 17, 2015 by Angel

Chemistry
A block of copper of unknown mass has an initial temperature of 69.1 ∘C . The copper is immersed in a beaker containing 93.4 g of water at 21.0 ∘C . When the two substances reach thermal equilibrium, the final temperature is 24.2 ∘C . Find mass of Copper
Tuesday, November 17, 2015 by Judy Blue

Chemistry
Calculate the pH during the titration of 40 ml of 0.1000 M HCl with 0.1000 M NaOH solution after the following additions of base: A.) 28.00 ML B.) 39.80 ML C.) 48.00 ML
Tuesday, November 17, 2015 by Braden

Chemistry
Fuel values, reported in units of KJ/g, are useful in comparing the efficiency of various energy sources on a mass basis. Determine the fuel value of the glucose and the tristearin. Which one, carbohydrates or fats, have the highest fuel value (and hence is the most efficient ...
Tuesday, November 17, 2015 by Anonymous

chemistry
I know everyone guessed i had a few more i couldnt do. Sorry but assistance please: 1.Sucralfate (molecular weight: 2087g/mol) is a major component of Carafate® which is prescribed for the treatment of gastrointestinal ulcers. The recommended dose for a duodenal ulcer is ...
Tuesday, November 17, 2015 by mikey

Chemistry (Help)
Calculate the DHrxn of C57H110O6 (s) + O2(g) --> CO2(g) + H2O(l) with DHf. C57H110O6(s) -390.70 O2(g) 0 CO2(g) -393.5 H2O(l) -285.840 I balanced the equation: 2C57H110O6 (s) + 163O2(g) --> 114CO2(g) + 110H2O(l) and my work: DHrxn = [224mol(-393.5+(-285.840))] - [165mol(-...
Tuesday, November 17, 2015 by Anonymous

Chemistry (Check)
Calculate the DHrxn of C6H12O6 (s) + O2 (g) --> CO2 (g) + H2O (l) with DHf. C6H12O6(s) -1260.04 O2(g) 0 CO2(g) -393.5 H2O(l) -285.840 I balanced the equation: C6H12O6 (s) + 6O2 (g) --> 6CO2 (g) + 6H2O (l) and my work: DHrxn = [12mol(-393.5+(-285.840))] - [7mol(-1260.04+0...
Tuesday, November 17, 2015 by Anonymous

chemistry
41. Ethyne, C2H2, used in welding react with oxygen as shown below.
Tuesday, November 17, 2015 by mark

chemistry
i am working on a practice worksheet and need help with a few i can not understand. please and thank you. I have to post them separately sorry 49.how many grams of water are needed to completely hydrolyze 30.8 g of the ester? A.0.416 g B.30.8 g C.11.3 g D.7.49 g 54. Sodium ...
Tuesday, November 17, 2015 by mark

Chemistry
al(i) Determine the number of moles of Ca2+ present in the titrated sample. (ii) Determine the [Ca2+] and hence the solubility of CaSO4.2H2O in the original 10.0 mL sample. so
Tuesday, November 17, 2015 by Mara

Chemistry
A 10.0 mL sample of supernatant liquid from the system described by equation 1 was titrated with 0.01022 M EDTA solution to an end-point at 16.90 mL. Titration of the blank gave a titre (end-point) at 1.45 mL. Determine the titration volume required to titrate the Ca2+ alone.
Tuesday, November 17, 2015 by Mara

CHEMISTRY
An analysis of a compound gave 40% carbon 3.7% hydrogen. the vapour density of the compound is 30. calculate the empirical and molecula fomular.
Tuesday, November 17, 2015 by NEMUEL

chemistry
How many milliliters of water has been dispensed if the initial buret reading was 0.45 mL and the final is 20.33 mL?
Tuesday, November 17, 2015 by Anonymous

chemistry
how many grams of NaCl should be added in 15ml which must have a final concentration of 10mM
Tuesday, November 17, 2015 by Josh

Chemistry
Describe an experiment using only hot and cold water that would allow you to verify that the heat capacity of a coffee-cup calorimeter is about 1.0x10^1 J/oC. Be specific.
Tuesday, November 17, 2015 by Wex

Chemistry
Experimental results for hydrochloric acid (neutralization) are always a little less negative than the usual constant of heat of neutralization for strong acids and bases (-57.35kJ). Suggest reasons for this.
Tuesday, November 17, 2015 by Wex

chemistry
anyone know how to do this and which choice is correct?thank you so much in advance. Use the Henderson-Hasselbalch equation to calculate the pH of a buffer that is 0.350 M acetic acid and 0.250 M sodium acetate. a.4.89 b.4.47 c.4.59 d.none of the above is is not 4.74
Tuesday, November 17, 2015 by anna

chemistry
The following reaction can be written as the sum of two reactions, one of which relates to ionization energy and one of which relates to electron affinity: Li(g)+F(g)→Li+(g)+F−(g) What is the reaction that corresponds to the first ionization energy of lithium, Li? ...
Monday, November 16, 2015 by rabia

Chemistry
Ice has negative caloric count. How much energy, in each of the following units, does your body lose from melting 175g of ice? Express your answers in J, kJ, cal, Cal
Monday, November 16, 2015 by Nicole

Chemistry (Check)
Calculate the DHrxn of C57H110O6 (s) + O2(g) --> CO2(g) + H2O(l) with DHf. C57H110O6(s) -390.70 O2(g) 0 CO2(g) -393.5 H2O(l) -285.840 I balanced the equation and my work: DHrxn = [224mol(-393.5+(-285.840))] - [165mol(-390.70+0)] = -87706.66 KJ/mol Is this right? If not, ...
Monday, November 16, 2015 by Anonymous

Chemistry (Check)
Calculate the DHrxn of C6H12O6 (s) + O2 (g) --> CO2 (g) + H2O (l) with DHf. C6H12O6(s) -1260.04 O2(g) 0 CO2(g) -393.5 H2O(l) -285.840 I balanced the equation and my work: DHrxn = [14mol(-393.5+(-285.840))] - [7mol(-1260.04+0)] = -690.48 KJ/mol Is this right? If not, what ...
Monday, November 16, 2015 by Anonymous

Chemistry
Determined at which temperature is the solubility of KNO3 at 60 grams per 100 grams of water
Monday, November 16, 2015 by Tommy

Chemistry (Check)
The bond strengths of the compounds HF, HCl, HBr, and HI are as follows: compound bond strength, kJ/mol HF 569.87 HCl 431.62 HBr 366.35 HI 298.407 Briefly explain why the bond strengths are ranked in this order. My guess is: They are ranked in this order because of the ...
Monday, November 16, 2015 by Anonymous

Chemistry
What is the concentration of lead ions in a solution if they are completely precipitated from 36.3 mL of solution by 29.6 mL of 0.35M potassium iodide.
Monday, November 16, 2015 by Sam

chemistry
Determine the mass of copper that has the same number of atoms as there are in 15.46 mg of gold. Answer in units of mg.
Monday, November 16, 2015 by Quinton

chemistry
Determine the quantity (g) of pure CaCl2 in 7.5 g of CaCl2*9H2O
Monday, November 16, 2015 by ali

Chemistry
A 22.6 mL sample of a weak monoprotic acid, HX, requires 50.0 mL of 0.050 M NaOH to reach the equivalence point. After the addition of 30.0 mL of NaOH, the pH is 4.90. What is the Ka of HX?
Monday, November 16, 2015 by Lexi

chemistry
at 25 celcius, how many dissociated OH ions are there in 8.0x10^-1 L of aqueous solution with pH 4.73?
Monday, November 16, 2015 by Christine

Chemistry
Explain what would happen if a saturated solution of kno3 at 50°c is heated
Monday, November 16, 2015 by Miya pierre

Chemistry
2.0 gram of C2H4 is reacted withO2. What mass of water is produced?
Monday, November 16, 2015 by Cindy

chemistry
Which is the correct expression for Keq when the chemical reaction is as follows: N2 + 3H2 2NH3.
Monday, November 16, 2015 by luis

Chemistry
How do I know the order of placing dots on the lewis structure? Please give an example.
Monday, November 16, 2015 by Rucha

Chemistry
State the kind of intermolecular forces that would occur between the solute and solvent in barium nitrate (ionic). Check all that apply. ion-dipole hydrogen bonding dispersion dipole-dipole
Monday, November 16, 2015 by Desiree Torres

Analytical Chemistry
I have a 0.00156 M solution of CuSO4*5H2O in water (from 0.0398 g of CuSO4*5H20 in 100 mL of water). How would I calculate the ppm of Cu of that solution from that information? Now if I were to find ppm of Cu in different aliquots of this stock solution (5 mL, 10 mL, etc.) how...
Monday, November 16, 2015 by Ronnie

Chemistry
Experimental results for hydrochloric acid (neutralization) are always a little less negative than the usual constant (-57.35kJ). Suggest reasons for this.
Monday, November 16, 2015 by Wex

chemistry
What is the value of the equilibrium constant at 500 °C for the formation of NH 3 according to the following equation? N 2 ( g ) + 3H 2 ( g ) ⇌ 2NH 3 ( g ) An equilibrium mixture of NH 3 ( g ), H 2 ( g ), and N 2 ( g ) at 500 °C was found to contain 1.35 M H 2 , ...
Monday, November 16, 2015 by mayuri

chemistry
A reaction is represented by this equation: 2W( aq ) ⇌ X( aq ) + 2Y( aq ) K c = 5 × 10 −4 (a) Write the mathematical expression for the equilibrium constant. (b) Using concentrations of ≤1 M , make up two sets of concentrations that describe a mixture ...
Monday, November 16, 2015 by mayuri

chemistry
A reaction is represented by this equation: 2W( aq ) ⇌ X( aq ) + 2Y( aq ) K c = 5 × 10 −4 (a) Write the mathematical expression for the equilibrium constant. (b) Using concentrations of ≤1 M , make up two sets of concentrations that describe a mixture ...
Monday, November 16, 2015 by mayuri

Chemistry
Hydrocarbon burn in excess oxygen yields 4.4g of carbon(iv)oxide and 2 of 7g of water. Find the empirical formula of hydrocarbon
Monday, November 16, 2015 by Prudent

chemistry
0.60g of a gaseous hydrocarbon E when completely burnt in oxygen gave 1.76g of carbon dioxide. WHAT IS THE EMPIRICAL FORMULA OF E?
Monday, November 16, 2015 by viky

Science: Chemistry
How many kilojoules are released when 115 g of Si reacts with chlorine? Si(s)+2Cl2(g)→SiCl4(g)ΔH=W​22;657kJ
Sunday, November 15, 2015 by Alex

Science: Chemistry
Pentane (C5H12) burns in oxygen to produce carbon dioxide and water. C5H12(g)+8O2(g)→5CO2(g)+6H2O(g) Calculate the mass of CO2 that can be produced if the reaction of 38.5 g of pentane and sufficient oxygen has a 58.0 % yield.
Sunday, November 15, 2015 by Alex

Chemistry
A 0.120 g sample of a diprotic acid of unknown molar mass is dissolved in water and titrated with 0.1218 M NaOH. The equivalence point is reached after adding 12.4 mL of base. What is the molar mass of the unknown substance?
Sunday, November 15, 2015 by Jorge

chemistry Dr BOB
In many residential water systems, the aqueous Fe3+ concentration is high enough to stain sinks and turn drinking water light brown. The iron content is analyzed by first reducing the Fe3+ to Fe2+ and then titrating with MnO4- in acidic solution. Fe2+(aq) + MnO4-(aq) ? Mn2+(aq...
Sunday, November 15, 2015 by Dalton

Analytical Chemistry
I have a 0.00156 M solution of CuSO4*5H2O in water (from 0.0398 g of CuSO4*5H20 in 100 mL of water). How would I calculate the ppm of Cu of that solution from that information?
Sunday, November 15, 2015 by Ronnie

Chemistry 102
The average human body contains 6.00 L of blood with a Fe2+ concentration of 2.00×10−5 M . If a person ingests 6.00 mL of 16.0 mM NaCN, what percentage of iron(II) in the blood would be sequestered by the cyanide ion?
Sunday, November 15, 2015 by Kyle

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